Companies are generating data at ever increasing rates which, in turn, makes data analysis an increasingly complex task. To reveal and benefit from information hidden in their data, analysts require easy to use tools. Challenges arise from the complexity of the data; typically, it is multi-dimensional and structured in complex hierarchies. One common representation of these types of structures is the use of data cubes. However, it is difficult for users to consider more than three dimensions. Additionally, non-linear hierarchies, such as time hierarchies, cannot be easily represented in such data cubes. As a consequence, analysts still need an appropriate representation for getting a quick overview of existing dimensions and their hierarchical structure.
In addition, analysts not only have to understand the structure of the data, they also need to navigate to different levels in the individual dimensions. As a result, data analysis tools require support for easy and fast navigation. Typically, navigation is accomplished using roll up and drill-down operations.